Engine secondary air injection control



1968 J. KNOWLES 3,397,534

ENGINE SECONDARY AIR INJECTION CONTROL Original Filed Dec, 20, 1965 .38-BYPASS AIR 34 I1 I I 32 AIR CONTROL VALVE PUMP VALVE ACTUATOR FIG.I

TRANSMISSION GOVERNOR AIR INJECTION MANIFOLD .5}? 7 7 FIG. 2

\ 4 0- 1? fa J J JAM ES K NOWLES lNVENTOR A 7' TORNEIS United StatesPatent 3,397,534 ENGINE SECONDARY AIR INJECTION CONTROL James Knowles,Bloomfield Hills, Mich., assignor to Ford Motor Company, Dearborn,Mich., a corporation of Delaware Continuation of application Ser. No.514,822, Dec. 20, 1965. This application Jan. 17, 1968, Ser. No. 698,66611 Claims. (CI. 60-30) ABSTRACT OF THE DISCLOSURE An internal combustionengine has a secondary air manifold supplied with air by an enginedriven air pump, the air being directed to the engine exhaust ports forchemical combination with unburned hydrocarbons in the exhaust gas, theair pump discharge flow being diverted from the air manifold above apredetermined vehicle speed by fluid from a vehicle speed responsivegovernor to reduce the load of driving the air pump and therebyconserving horsepower.

This application is a continuation of application Ser. No. 514,822,filed Dec. 20, 1965, which is now abandoned.

This invention relates, in general, to an internal combustion engine.More particularly, it relates to means for controlling the injection ofsmog controlling secondary air into an internal combustion engine.

With the increased interest in smog preventative devices, most enginesnow manufactured for use in motor vehicles have some means to reduce theoutput of unburned hydrocarbons and other harmful elements into theatmosphere. In some engines, this takes the form of an engine driven aircompressor that supplies a source of secondary air to the regionadjacent the engine exhaust ports for conversion of the unburnedhydrocarbons and other smog producing elements present in the exhaustgases into less harmful forms. In most cases, the air pump is drivencontinuously regardless of engine speed, and, therefore, uses up aconsiderable amount of useful horsepower.

Engines, as a rule, produce the greatest amount of smog inducingelements at low speeds when the air-fuel ratios of the combustiblemixtures are other than optimum. As engine speed increases, thepercentage of harmful unburned hydrocarbons and other elements presentin the combustion product gases decreases, and therefore, little if anyadditional or secondary air is needed at higher engine speeds. With thepresent commercial constructions, however, no provision is made forcontrolling the supply of secondary air; in most cases, it is suppliedas long as the engine is operating. This results in a considerable wasteof horsepower to drive the pump at higher speeds.

Therefore, it is a primary object of the invention to provide a controlfor a fluid pump that automatically reduces the load on the pump uponthe attainment of a predetermined vehicle speed.

It is another object of the invention to provide a control for an enginedriven air pump that below a predetermined vehicle transmission speedsupplies secondary air to an air injection manifold of the engine foranti-smog purposes, and above a predetermined vehicle speed diverts thepump output to reduce the horsepower needed to drive the pump.

It is a still further object of the invention to provide an internalcombustion engine secondary air injection manifold control that includesan air diversion valve spring biased to one position below apredetermined vehicle speed to supply air to the manifold, and movableto a second position by a vehicle speed responsive fluid pres- 3,397,534Patented Aug. 20, 1968 sure governor signal force above a predeterminedvehicle speed to divert the air supply either back to the inlet of thepump or out to ambient air.

Other objects, features and advantages of the invention will becomeapparent upon reference to the succeeding, detailed description thereof,and to the drawings illustrating the preferred embodiment thereof;wherein,

FIGURE 1 shows, schematically, an air flow control system embodying theinvention; and,

FIGURE 2 shows a cross-sectional view of portions of the system ofFIGURE 1.

FIGURE 1 shows a conventional motor vehicle type internal combustionengine 10 drivingly connected to a transmission 12 having a power outputshaft 14. Transmission 12 preferably would be of the automatic type, fora purpose that will become clear later. For example, it could be of themultiple of planetary gearset type shown in U.S. 3,103,831 that providesa plurality of forward speed drives and a reverse drive, the forwardspeed drive being obtained automatically as a function of the changes invehicle speed and torque demand by the operator. Power output shaft 14,in this case, would be connected through the conventional differentialgearing (not shown) to the driving rear axle shafts that are operablyconnected to the driving wheels of the motor vehicle in a known manner.

Transmission 12, in this case, contains a known type of fluid pressuregovernor indicated in general at 16. The governor could be similar tothat indicated at 216 in FIGURE 2 of the above-mentioned U.S. 3,103,831,and the details of construction and operation are, therefore, not given.Sufiice it to say that the governor would be driven by the transmissionpower output shaft 14, and would supply a fluid pressure in a line 18that varies in a parabolic manner as of the square of the speed of shaft14. Since shaft 14 is operably connected to drive the vehicle wheels,governor 16 therefore provides a varying fluid pressure that isindicative of the changes in vehicle speed. The known governorsgenerally have one or more stages of operation providing varying ratesof change in the pressure.

Engine 10, in this case, has a conventional air filter 20 covering theprimary air inlet to the conventional carburetor (not shown). Air takenthrough filter 20 passes into the main air induction system, combiningwith the necessary fuel for combustion in the engine cylinders. Theengine also has conventional exhaust manifolds 22 and 24 connecting thecombustion product gases from the exhaust valve ports (not shown) to theexhaust system.

Engine 10 is also provided with a secondary air injection manifold 26that has a plurality (corresponding to the number of cylinders) ofbranch conduits 28 each of which terminate in the region of the engineexhaust valve ports; that is, in a region where the gases are ex haustedfrom the cylinder combustion chambers. Manifold 26 is supplied withsecondary air from an engine driven air pump 30 that discharges airthrough a line 32.

In general, air discharge line 32 is controlled by a valve mechanism 34containing a valve that is normally spring biased to a positionconnecting discharge line 32 and a line 36 connected to manifold 26. Thecontrol valve is adapted to be acted upon by the governor fluid pressure signal force in line 18 so that above a predetermined vehiclespeed, the control valve will be moved to a position blockingcommunication between lines 32 and 36, while connecting line 32 to abypass line 38. The bypass line is shown as discharging to atmosphere;however, it is within the scope of the invention to connect the bypassline back to the inlet of air pump 30 to lower the pumping requirementsof the pump and increase its operating efficiency.

FIGURE 2 shows the details of construction of air pump 30 and thecontrol valving 34. More specifically, the pump is of the centrifugaltype and includes a semitoroidal shell 42 that is welded or otherwisesecured to one side of a V-type drive pulley 44. The pulley has a beltdrive connection (not shown) to the engine crankshaft, and is fixed onsleeve 46. The sleeve is rotatably mounted on a stationary shaft 48 by apair of spaced annular ball bearing units 50 and 52. The ends of thesleeve are suitably sealed as shown.

Shell 42 supports a number of circumferentially spaced impeller or pumpblades 54 that are dish-shaped in cross section. The shell or casing 42cooperates with and faces a semi-toroidal shaped stationary or statorcasing 56 that is hollow and bladeless. The stator has an air inletopening 58 and a fluid discharge outlet 60 located on oppositecircumferential sides of a narrow block seal member 62. The block sealprevents direct communication between the inlet and outlet, and forcesthe fluid to travel around the toroidal path between in a known manner.The stator 56 has a hub 66 fixedly secured to shaft 48, which isthreadedly secured in a stationary part 67 of the engine 10.

The axial spaces 68 and 69 between the outer and inner radial portionsof the pump and stator are sealed by a pair of elastomeric sealing rings70 and 72. These rings are each cemented or bonded in a suitable mannerto extensions 74 and 76, respectively, of stator 56. They cooperate withexternal flanges or lips 78 and 80 provided, respectively, on theradially outward portion of impeller shell 42 and the inner radialportion of pulley portion 44. During initial rotation of impeller shell42, each lip 78 and 80 will cut its own path into the respectiveelastomeric ring 70 and 72 to form an effective seal against leakage.The labyrinthian passages 82 and 84 formed by the shell extensions alsominimizes circumferential leakage of outlet fluid back to the inlet.

In operation, rotation of impeller shell 42 by pulley 44 causes air tobe drawn in through inlet 58 and centrifuged around the toroidal circuitwith a helical spiral motion in a known manner until it reaches theblock seal member 62, at which point the fluid is diverted into theoutlet 60 and into line 32. At this point, it enters the control valveassembly 34 under pressure.

The assembly 34 includes a spool valve 86 that is slidably mounted inthe bore 88 of a valve body 90. Opposite ends of the bore are connectedrespectively to the air pump discharge line 32 and to the governor fluidpressure signal line 18. Laterally spaced portions of the bore 88 areconnected to the atmospheric vent line 38 and to the supply line 36leading to secondary air injection manifold 26.

The spool valve 86 has a pair of spaced lands 92 and 94 interconnectedby a neck portion 96 to define an annular air chamber 100. The valve isnormally biased to the position shown by a spring 98 to block flowbetween inlet 32 and vent 38, Land 92 contains an unrestricted airpassage 102, which, in the position of the valve shown, connects the airin line 32 directly to line 36 to supply the engine with secondary air.When the vehicle speed attains a predetermined level of say 50 miles perhour, for example, the fluid pressure in line 18 acting against theright end of valve land 94 will have risen to a value suflicient toovercome the force of spring 98 and air pressure acting against land 92to move the valve to the left. This will block flow between lines 32 and36 and connect lines 32 and 38 through passage 102. At thispredetermined vehicle speed, therefore, the discharge of air from theair pump will be diverted from the secondary air injection manifold 26,and vented. When the air is vented or bypassed, the back pressure on thepump from manifold 26 decreases; thus, the load on pump 30 issubstantially reduced, and only very little horsepower now is requiredto drive it.

Valve 86 is shown as having a pair of buttons 104 on the right face ofland 94 to space the valve from the end of bore 88. This permitsgovernor pressure in line 18 to act over the full area of this portionof the land. If desired, the buttons could be omitted to provide a quickmovement to the valve; that is, when land 94 is seated flat against theend of the bore, the pressure acting against the small area of the landdefined by the diameter of conduit 18 will determine the time ofmovement of the valve. However, as soon as the valve moves, the suddenincrease in area upon which the fluid acts causes a rapid movement ofthe valve to the left to connect lines 32 and 38 and disconnect line 36from fluid chamber 100.

From the foregoing, it will be seen that the invention provides a simpleand yet reliable method of restricting the flow of secondary air to theengine secondary manifold at a time when it is not necesary or desired.This results in lowering the horsepower required to drive the air pump,which results in a more economical operation of the engine.

While the invention has been illustrated in its preferred embodiment inthe figures, it will be clear to those skilled in the arts to which theinvention pertains that many changes and modifications may be madethereto without departing from the scope of the invention.

I claim:

1. An air pump control for use in an engine driven motor vehicle havingan exhaust system comprising, in combination, an air pump driven by saidengine and discharging air under pressure into the exhaust system ofsaid engine, and control means cooperating with said pump and vehicleresponsive to a predetermined vehicle speed to divert said discharge ofair from said exhaust system of said engine.

2. A control as in claim 1, said pump comprising an air compressor, saidexhaust system including an air injection manifold.

3. A control as in claim 2, said manifold having an air inlet operablyconnected to said compressor and outlets operably associated with theengine exhaust gas manifold.

4. A control as in claim 2, said vehicle having a transmission driven bysaid engine and having a power output shaft operably driving saidvehicle, fluid pressure governor means driven by said output shaftproviding a fluid pressure signal force that increases as a function ofthe increase in speed of said shaft, said control means being acted uponby said governor pressure.

5. A fluid control for use in a motor vehicle, comprising, incombination, an internal combustion engine having a fluid injectionmanifold provided with a fluid inlet and a pluralty of outlets, a fluidpump driven by said engine and providing a source of fluid at varyingpressures, a vehicle speed responsive fluid pressure signal meansproviding a source of fluid under pressure that varies as a function ofthe speed of said vehicle, conduit means connecting the fluid underpressure from said pump to said manifold, control means in said conduitmeans movable between positions supplying and preventing, respectively,the flow of fluid from said pump to said manifold, and means connectingsaid vehicle speed responsive pressure signal to said control means toact thereon and move said control means above a predetermined vehiclespeed to a position preventing flow of fluid to said manifold.

6. A control as in claim 5, said pump comprising an air compressor, saidmanifold outlets being connected to the region adjacent the engineexhaust valve ports.

7. A control as in claim 5, said speed responsive fluid pressure meanscomprising a fluid pressure governor driven by the vehicle transmissionpower output shaft.

8. A control as in claim 5, said control means including a valve springbiased to a position connecting said pump and manifold and movable bysaid pressure signal force to a position preventing communicationtherebetween.

9. A control, as in claim 5, said pump comprising an air compressor,said manifold outlets being connected to the region adjacent the engineexhaust valve ports, said speed responsive fluid pressure meanscomprising a fluid pressure governor driven by the vehicle transmissionpower output shaft, said control means including a valve spring biasedto a position connecting said pump and manifold and movable by saidpressure signal force to a position preventing communication betweensaid pump and manifold.

10. A control as in claim 5, said manifold constituting an enginesecondary air supply source separate from the main engine air inductionsystem.

11. A fluid pump control for use in an engine driven motor vehicle,comprising, in combination, a fluid pump driven by said engine anddischarging fluid under pressure into portions of said engine, andcontrol means cooperating With said pump and vehicle responsive to apredetermined vehicle speed to divert said discharge of fluid from saidengine portions, said pump comprising an air compressor, said engineportions including an air injection manifold, said manifold having anair inlet operably connected to said compressor and outlets operablyassociated with the engine exhaust gas manifold.

References Cited UNITED STATES PATENTS 1,979,488 11/1934 Perez 74472.13,060,678 10/1962 Ridgway -30 3,305,042 2/1967 Thorner 106 RALPH D.BLAKESLEE, Primary Examiner.

